用化學平衡法研究Fe—Nb—C熔體的熱力學

Thermodynamic Study of Fe-Nb-C Melts Using the Chemical Equilibrium Method

摘要: CO-CO₂混合氣與Fe-Nb-C熔體和NbO₂（s）的平衡實驗是在Al₂O₃或ZrO₂坩堝中進行的。實驗表明,在1073～1273K間的低溫下產生碳沉積是不可避免的。熔體上方的氣相氧分壓用固體電解質電池測定。與熔體中Nb成平衡的氧化物被確定為NbO₂（s）。測得1823K時反應Nb+O₂=NbO₂（s）的平衡常數K=6.31×10¹⁰,因此,可得反應的標準自由能:
ΔG°=-377150（J/mol）
求出了碳對Nb和Nb對碳的活度相互作用系數為:
\rme\frac\rmC\rmNb=-0.74;\rme\frac\rmC\rmNb=-0.092

Abstract: The equilibrium of gaseous CO-CO₂ mixture with liquid iron-Niobium-Carbon alloys and NbO₂(s) contained in Al₂O₃ or ZrO₂ crucible is discribed. It shows that the deposition of carbon is inevitable in the low temperature zone(from 1073 to 1273K). The equilibrium partial pressure of oxygen in gaseous on the surface of the melt has been determined with the solid electrolyte cell.The oxide in equilibrium with the niobium in the melt is considered to be NbO₂ (s). The equilibrium constant for the reactionNb + O₂=NbO₂ (s)at 1823K is:K=6.31×10¹⁰ therefore the standard free energy is
△G°=-377150 (J/mol)
The interaction coefficients of activity evaluated, are
\rme\frac\rmC\rmNb=-0.74;\rme\frac\rmC\rmNb=-0.092.